Pneumatic saw



` LM. ABRAMS. PNEuMAnc'sjAw.

l APPLICATION FILED SEPT. 24. l9l8. 1,306,395. Patented June10,1919.

s Y v |l Y): H 1 I fluid under pressure.

l .101m M. Ariaans, or BRooxLYN, NEW YORK. l

PNEUMATIC SAW.

Specification of Letters Patent.

Patented June' 1o, i919.

Application led September 24, 1918. Serial N o. 255,521.

To all 'whom it may concern:

Be it known that I, JOHN M. ABRAMS, a citizen of the United States, and a resident of Brooklyn, in the county of Kings and State of New'York, have invented certain new and useful Improvements in Pneumatic Saws, of which the following is a specification.

The invention relates to Ifluid-actuated and automatic tool opera-ting devices, and more particularly to such as are designed for the operation of cutting tools, for example of the character of a saw. In devices of this character, the cutting-action is effected preferably on the inward stroke of a reciprocatory member controlled by a suitable motive Such apparatus allows of rapid working of the wood and is particularly suitable for use in Shipyards where Wood is used to a large extent in the construction of various types of marine craft. The ordinary type of pneumatic tool,

with its rapidly moving and forceful plunging piston is entirely unsuitable for this class of work; and it is the object of the present invention to provide a device of the 'character' aforesaid which shall be simple in construction, positive in its action, and which will afford a. suliiciently powerful and uniform pull on theV toll member.

A further object of the invention consists in novel means for controlling the supply of fluid andthe arrangement of same in relation to the ports of the device.

The nature of the invention 4will be best understood when described in connection with` the accompanying dra-wings, in which- Figure 1 is a front elevation illustrating the invention as embodied in an automatically operated saw. Fig. 2 is a longitudinal section4 thereof.

Fig. 3 is a fragmentary longitudinal seetion illustrating the relation of the various members at the completion of the cutting stroke.

Figsfl and 5 are transverse sections taken respectively on the lines 4 4 and 5--5, Figs. 1 and 3. l

Similar characters of reference designate corresponding parts throughout the several views.

Referring to the drawings, 10 designates a partly open casing suitably bored to provideI a cylinder 11 in which is adapted to reciprocate a hollow piston member 12. The latter carries a rod which at its outward end has secured thereto the shank 13 of the tool, for examp'le, a saw blade 14, said rod passing through a suitable stuffing box 1 5 at the forward end ofthe cylinder and which closes the latter at this end. jPiston 12 is guided against rotational movement through a feather 16 of substantial proportions at taehed to said piston and movable with same in a guide-way or cutaway portion 17 of the cylinder wall. At the opposite end, the cylinder is closed by a head 18 which carries at its extreme outer end a handle 10 and control mechanism for the admission of fluid, said handle and head for this purpose being provided with the passageway 20, adapted to communicate with the interior of the'cylinder, and to which external connection may be made in any suitable manner.- The casing carries also at its forward end a further handle 21. The foregoing features form no essential part of thev invention, which relates more particularly to the manner of effecting the reciproeation of the piston 12 to provide a powerful anduniform pull on the Saw blade, preferably, during the inward stroke of said piston.

To this end, the passage of fluid through passageway 20 is interrupted by means of an automatic valve member 22 adapted to'rec'iproc-ate, without rotary movement, at right angles to the longitudinal axis of the piston 12 in a valve chamber v23 provided in the head of casing 10. This valve is springurged in one direction, across the axis of the piston, and has extending therethrough a duct 24'which is adapted to afford communication, when the valve is i'n the position indicated in Fig. 3, between passageway 20 and the interior of thel cylinder at the inward end of the latterthrough an inlet p'ort 25 thereof. The valve is maintained in this position under the influence of fluid under suitable pressure, as will be hereinafter more fully set forth.

In the position-indicated in Fig. 2 of the drawings, the valve 22, through a further duct 26 therein, affords arelief passageway between the interior of the cylinder and an exhaust port 27 in the head of casing 10, the said port 27 being also adapted to communi cate with the said valve chamber 23.

ln this position, a further duct 30, passing through the valve member 22, affords communication between the passageway 20 and a passageway B1 extending longitudinally of the casing 10 to the forward end. of the cylinder and providing an inlet port 32 in the extreme forward end thereof. At the eX- haus't end, the valve chamber 23 Ais in free communication with a passageway 33 extending longitudinally of the casing 10 to the forward end of the cylinder, and terminating in a port 3l opening therein between the extreme inward and outward positions of the piston. The cylinder itself, moreover, is provided with an exhaust port 35 adapted to Ibe uncovered when the piston reaches its extreme outward position.

The operation of the device is as follows. Assuming the members in the position as indicated in Figgglofthe drawings, with the piston at the extrelfi'e outward limit of its stroke, valve member 22` is in such position that its port 30 will cause the fluid under pressure to act behind the said piston, being introduced through the port 32, and effect its return movement until this source is cut off. This occurs after the piston passes the port 34, causing the fluid under high pressure to enter passageway 33 and act upon the end of valve 22 to return same in opposition to its spring to the position indicated in Fig. 3 of the drawings. Communication is thereby afforded through the rpassageway 2O and duct 24 to the opposite end of the cylinder to return the piston in position for its operative stroke. As soon as the piston on the return stroke passes beyond the port 34, no further fluid under high pressure is supplied to the valve chamber, and that rfeiiiaining becomes exhausted throughthe exhaust port 27; whereupon, the spring urged valve member is returned to the position indicated in Fig. 2, and the cycle of the operations is repeated. Duct 26, being in communication with the exhaust port 27, affords a relief passageway or the exhausting of the remaining fluid under pressure in the inner end of the cylinder.

and an additional exhaust port between the I limits of travel of the outer end of said piston; of a valve to control the supply of fluid to said supply port and to the inlet port, and actuated in one direction of its movement by the fluid delivered through said intermediate port.

2. In a fluid actuated tool: the combination with the cylinder thereof and its piston, said cylinder being provided with a liuid supply port at its extreme outer end, an inlet vport at its extreme inner end, an exhaust port adapted to be uncovered by the inner end of the said piston when it has reached' stroke, and an the outward position of its additional exhaust port between the limits of travel of the outer end of said piston; of a valve to control the supply of fluid to said supply port and to the inlet port and actu` ated in one direction of its movement by the fluid delivered through port, and resilient means operating to urge said valve in the opposite direction.

Signed at Brooklyn, in theI county of Kings and St. te of New Yorkthis 20th day of September, A, D. 1918.

JOHN M. ABRAMS.

Witnesses: j A

MILTON A. SULLIVAN, J oHN S. MAHER.

said intermediatevv 

